ABB Relion 670 Series Technical Reference Manual page 473

1MRK505222-UUS C
Technical reference manual
In this case the logic is realized within the function. If the inputs are indicating pole
discrepancy the trip timer is started. This timer will give a trip signal after the set delay.
Pole discrepancy can also be detected by means of phase selective current
measurement. The sampled analog phase currents are pre-processed in a discrete
Fourier filter (DFT) block. From the fundamental frequency components of each phase
current the RMS value of each phase current is derived. The smallest and the largest
phase current are derived. If the smallest phase current is lower than the setting
CurrUnsymPU times the largest phase current the settable trip timer (tTrip) is started.
The tTrip timer gives a trip signal after the set delay. The TRIP signal is a pulse 150
ms long. The current based pole discrepancy function can be set to be active either
continuously or only directly in connection to breaker open or close command.
The function also has a binary input that can be configured from the autoreclosing
function, so that the pole discrepancy function can be blocked during sequences with a
single pole open if single pole autoreclosing is used.
BLOCK
OR
BLKDBYAR
PolPosAuxCont
52b_A
52a_A
Pole
52b_B
52a_B Disc repancy
52b_C detection
52a_C
PD signal from CB
EXTPDIND
CLOSECMD t+ 200 ms
OR
OPENCMD
Unsymmetry current
detection
ANSI05000747 V1 EN
Figure 236: Simplified block diagram of pole discrepancy function CCRPLD (52PD)
- contact and current based
CCRPLD (52PD) is disabled if:
• The IED is in TEST mode and CCRPLD (52PD) has been blocked from the local
HMI
• The input signal BLOCK is high
• The input signal BLKDBYAR is high
AND
AND
OR
AND
AND
Section 7
Current protection
150 ms
TRIP
0 - t
0
en 05000747 _ansi.vsd
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